Bill Turner wrote:
>ORIGINAL MESSAGE:
>
>On Sat, 15 Mar 2008 14:43:18 -0500, K4SAV <RadioIR@charter.net> wrote:
>
>
>
>>It is interesting to compare Cebik's calculations for gain versus number
>>of radials with that which W8JI measured. Cebik calculated that the
>>gain difference between 4 radials and 64 radials was 1.2 dB. W8JI
>>measured 5.5 dB difference between 4 and 60 radials.
>>
>>
>
>------------ REPLY FOLLOWS ------------
>
>The difference is no doubt due to differences in ground conductivity. If
>you live over highly conductive ground, the number of radials would have
>less impact. Over poor ground, the more radials, the less loss.
>
>73, Bill W6WRT
>
>
>
--------------------------------------
Poor ground does make the difference larger, but to account for a gain
difference of 5.5 dB in NEC, the ground quality at W8JI would have to be
poorer that that in downtown New York City in the middle of the high
rise buildings. If it was only just very poor, or equal to that of a
typical city, the gain difference would have only been 2.3 dB as
calculated by NEC. W8JI's ground may not be as good as some of the
mid-western states, but it is no where near that of the downtown area of
a city.
Jerry, K4SAV
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